Related-art solar power generation apparatuses generally have such a form that plural solar cell panels are laid over a surface in orientation facing the sun. As one example, there is known a solar power generation apparatus of the type that plural solar cell panels are laid over the roof of a building or a house. In general, the solar cell panels are formed of opaque semiconductors, and they cannot be arranged in stacked relation. Therefore, a large-area solar cell panel is required to obtain a sufficient amount of electric power. On the other hand, there is a restriction that the apparatus has to be installed in a place, such as a roof, where an available area is limited. This has led to a limit in the amount of electric power obtained. Moreover, because the weight of the solar cell panel increases due to the associated protective glass, wired lines, and so on, the apparatus can be installed only over the roof having high strength.
In view of the situations mentioned above, the so-called “window-surface solar-cell power generation system” is proposed in which solar cells are installed in window portions that occupy a large area in a building (see Patent Literature (PTL) 1 listed below). The proposed window-surface solar-cell power generation system includes a light absorptive-emissive plate in which a phosphor is dispersed, and a solar cell, wherein a window frame is constituted by bonding the solar cell to a side surface of the window frame, the side surface being positioned perpendicular to a day-lighting surface of the light absorptive-emissive plate. In the window-surface solar-cell power generation system, the phosphor in the light absorptive-emissive plate is excited by the sunlight incident upon the light absorptive-emissive plate, and the solar cell is illuminated with radiant light from the phosphor, whereby electric power is generated.
There is also proposed a solar cell including a light collector that introduces the incident sunlight to the solar cell (see PTL 2 listed below). The light collector of the solar cell, disclosed in PTL 2, includes a light collecting member that has a flat incident surface and a scattering surface, the latter being positioned to face the incident surface with a gradually increasing distance kept from the incident surface, and to scatter light input through the incident surface. The solar cell is installed at an end surface of the light collecting member.